(a) Field of the Invention
The present invention relates to a layered electrophotographic element comprising a charge generating layer consisting essentially of a charge generating agent composed of a specific disazo pigment and a charge transfer layer consisting essentially of a charge transfer agent composed of a specific carbazole derivative and a specific binder.
(b) Description of the Prior Art
Layered electrophotographic elements of the type of comprising an electroconductive support on which there is formed in turn a charge generating layer and a charge transfer layer, said charge generating layer being consisted essentially of a charge generating agent such as monoazo pigment, disazo pigment or the like, said charge transfer layer being consisted essentially of a charge transfer agent such as fluorenone derivative, carbazole derivative or the like and a resin binder of every kind, are well known. In such multi-layered electrophotographic elements as mentioned above, their electrostatic characteristics depend mainly on the basic materials used, namely the combinations of charge generating agents with charge transfer agents, while their mechanical characteristics and physical properties such as surface property, external appearance and the like depend mainly on the binders incorporated in the charge transfer layers. Preferably, these properties should be neither changed nor deteriorated with the lapse of time or owing to their repeated use. In the case where durability is demanded of these properties, however, it is to be noted that the binders contained in the charge transfer layers tend to exert a great influence thereupon. In order to obtain the layered electrophotographic elements having durability as well as electrostatic characteristics, mechanical characteristics and physical properties, importance should be attached to selection of not only the basic materials but also the binders to be used. However, conventional layered electrophotographic elements could not meet all these properties simultaneously.